The man arrived at the hospital in the early hours of Monday morning with fever and gastrointestinal symptoms that were consistent with Ebola, a Mount Sinai Hospital spokesman told MedPage Today by email.

The patient is in "strict isolation" at the hospital while he is tested for Ebola, the spokesman said in a statement, but also for other diseases that could cause the symptoms.

"All necessary steps are being taken to ensure the safety of all patients, visitors, and staff," the statement said. Further details, such as the patient's name, occupation, and the West African country to which he had travelled, were not released.

In a Health Alert Network last week, the CDC urged healthcare providers to be on the lookout for cases symptoms and risk factors "consistent" with Ebola infection.

Those factors, the CDC said, are:

Clinical criteria, which includes fever of greater than 38.6ºC or 101.5ºF, and additional symptoms such as severe headache, muscle pain, vomiting, diarrhea, abdominal pain, or unexplained hemorrhage.

And epidemiologic risk factors within the 3 weeks before the onset of symptoms -- contact with blood or other body fluids of a known or suspected Ebola patient, living in or traveling to places where Ebola transmission is active, or handling bats, rodents, or primates from disease-endemic areas.

The agency noted that malaria should be part of the differential diagnosis, because it is a common cause of febrile illness in people who have travelled to the affected countries -- Guinea, Liberia, and Sierra Leone.

The CDC said U.S. hospitals "can safely manage a patient with (Ebola) by following recommended isolation and infection control procedures."

The New York case comes as Emory University Hospital in Atlanta is caring for Kent Brantly, MD, who was infected while he was working in Liberia at a medical center treating Ebola patients.

A second American patient is to be airlifted to Emory shortly.

Late Monday, the World Health Organization said the Ebola toll had risen to 1,603 suspected to confirmed cases in the three countries, with 887 deaths.

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